Pulmonary and cerebral damage in COVID-19 survivors: is there any association?

BACKGROUND: COVID-19 primarily affects the respiratory system, with pulmonary function tests (PFTs) evaluating respiratory impairments and chest CT imaging revealing structural lung abnormalities. However, the disease's multisystem impact - including vascular dysfunction and neurological complications associated with MRI neuroimaging alterations - raises the possibility of shared mechanisms underlying both pulmonary and cerebral involvement, potentially mediated by vascular damage. MATERIALS AND METHODS: The study included 27 consecutive COVID-19 patients (median age 59.0 [IQR 50.5 - 70.0] years, 37% female) presenting with concurrent respiratory and neurological symptoms. All patients underwent PFTs, chest CT, and brain MRI. CT images were processed to quantify lung parenchyma, airways, and vasculature, including small-vessel volume (SVV) and air-to-perfusion ratio (APR). Brain MRI analysis assessed gray matter (GM) integrity (volume and cortical thickness), white matter (WM) diffusion metrics (Apparent Diffusion Coefficient, ADC), and GM perfusion (cerebral blood volume, CBV; cerebral blood flow, CBF). Relationships between pulmonary and cerebral metrics were explored using Spearman correlations and multivariable linear regression. RESULTS: GM volume was positively associated with diffusing capacity for carbon monoxide (DLCO), and cortical thickness was positively associated with alveolar volume (VA). No associations were observed for WM ADC. In contrast, lower pulmonary function (DLCO, VA, forced expiratory volume in 1 s (FEV1), and forced vital capacity (FVC)) were associated with higher GM perfusion. CONCLUSIONS: COVID-19-related pulmonary impairment is associated with reduced GM structural integrity and altered cerebral perfusion, suggesting a lung-brain interplay potentially driven by systemic vascular dysfunction and adaptive cerebrovascular mechanisms. These findings underscore the importance of integrated pulmonary and neurological assessment in post-COVID-19 patients and highlight the need for longitudinal studies to clarify the evolution and clinical consequences of these alterations.